1. Field of the Invention
The present invention relates to an optical navigation device and, more particularly, to an optical navigation device and a method of operating the same that are capable of preventing malfunction of the optical navigation device, which may be generated when the optical navigation device is spaced apart from a work surface, and minimizing unnecessary power consumption.
2. Description of the Related Art
An optical navigation device such as an optical mouse is a device for calculating a movement value from variation of an image of a work surface. Therefore, it is very important to precisely detect the image of the work surface. Hereinafter, the optical navigation device will be described using an optical mouse for the convenience of description.
As shown in FIG. 1, an optical mouse should be positioned on a work surface. A light source 8 radiates light 7 onto the work surface 2, and an image sensor 3 collects light 6 reflected by the work surface 2 through a lens 4 to precisely obtain an image of the work surface 2.
However, since the optical mouse is manipulated by a user's hand, the optical mouse may be spaced apart from the work surface by movement of the user's hand, and therefore, the optical mouse may obtain an inaccurate image of the work surface to calculate an incorrect movement value.
In addition, in order to minimize unnecessary power consumption, a conventional optical mouse operates in an inactive mode when the optical mouse does not operate during a predetermined time. However, when the optical mouse is spaced apart from the work surface, since an image irrelevant to movement of the optical mouse is detected due to peripheral illumination (for example, light of a fluorescent lamp), the optical mouse cannot operate in the inactive mode, even though there is no movement of the optical mouse.